Gestational diabetes: fasting capillary glucose as a screening test in a multi-ethnic, high-risk population

Self-administered oral glucose tolerance test with capillary glucose measurements for the screening of diabetes mellitus in high-risk adults: a feasibility study

INTRODUCTION

Early diagnosis of prediabetes based on blood sampling for the oral glucose tolerance test (OGTT) is crucial for intervention but multiple barriers hinder its uptake. This study aimed to assess the feasibility and precision of a self-administered capillary OGTT for type-2 diabetes mellitus (T2DM) in high-risk individuals.

RESEARCH DESIGN AND METHODS

Participants with history of gestational diabetes or prediabetes were recruited in primary care. Due to their prediabetic status and previous diagnosis of gestational diabetes mellitus, a proportion of participants had previous experience doing OGTT. They self-administered the capillary OGTT and concurrently their venous glucose samples were obtained. They filled a questionnaire to collect their demographic information, views of their capillary OGTT, and their preferred site of the test.

RESULTS

Among 30 participants enrolled in this feasibility study, 93.3% of them felt confident of performing the capillary OGTT themselves, and 70.0% preferred the test at home. Older, less educated participants found it less acceptable. Mean capillary glucose values were significantly higher than venous glucose values, with mean difference at 0.31 mmol/L (95% CI 0.13 to 0.49) at fasting, and 0.47 mmol/L (95% CI 0.12 to 0.92) 2 hours post-OGTT. Capillary and venous glucose measurements were correlated for fasting (r=0.95; p<0.001) and 2-hour-post-OGTT (r=0.95;p<0.001). The Fleiss-Kappa Score (0.79, p<0.0001) indicated fair agreement between the two methods. The capillary OGTT had excellent sensitivity (94.1%) and negative predictive value (NPV=91.7%) in identifying prediabetes or T2DM status, vis-a-vis to venous glucose samples.

CONCLUSION

Self-administered capillary OGTT is feasible and acceptable, especially among younger adults, with excellent sensitivity and NPV compared with plasma-based OGTT.

Prevalence of Gestational Diabetes Mellitus in the Middle East and North Africa, 2000-2019: A Systematic Review, Meta-Analysis, and Meta-Regression

Women in the Middle East and North Africa (MENA) region are burdened with several risk factors related to gestational diabetes mellitus (GDM) including overweight and high parity. We systematically reviewed the literature and quantified the weighted prevalence of GDM in MENA at the regional, subregional, and national levels. Studies published from 2000 to 2019 reporting the prevalence of GDM in the MENA region were retrieved and were assessed for their eligibility. Overall and subgroup pooled prevalence of GDM was quantified by random-effects meta-analysis. Sources of heterogeneity were investigated by meta-regression. The risk of bias (RoB) was assessed by the National Heart, Lung, and Blood Institute's tool. One hundred and two research articles with 279,202 tested pregnant women for GDM from 16 MENA countries were included. Most of the research reports sourced from Iran (36.3%) and Saudi Arabia (21.6%), with an overall low RoB. In the 16 countries, the pooled prevalence of GDM was 13.0% (95% confidence interval [CI], 11.5-14.6%, I² , 99.3%). Nationally, GDM was highest in Qatar (20.7%, 95% CI, 15.2-26.7% I² , 99.0%), whereas subregionally, GDM was highest in Gulf Cooperation Council (GCC) countries (14.7%, 95% CI, 13.0-16.5%, I² , 99.0%). The prevalence of GDM was high in pregnant women aged ≥30 years (21.9%, 95% CI, 18.5-25.5%, I² , 97.1%), in their third trimester (20.0%, 95% CI, 13.1-27.9%, I² , 98.8%), and who were obese (17.2%, 95% CI, 12.8-22.0%, I² , 93.8%). The prevalence of GDM was 10.6% (95% CI, 8.1-13.4%, I² , 98.9%) in studies conducted before 2009, whereas it was 14.0% (95% CI, 12.1-16.0%, I² , 99.3%) in studies conducted in or after 2010. Pregnant women in the MENA region are burdened with a substantial prevalence of GDM, particularly in GCC and North African countries. Findings have implications for maternal health in the MENA region and call for advocacy to unify GDM diagnostic criteria.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018100629.

Diagnostic accuracy of the triglyceride-glucose index for gestational diabetes screening: a practical approach

The oral glucose tolerance test (OGTT) remains as the gold standard to diagnose gestational diabetes mellitus (GDM); however, this test may be inconvenient and costly. Hence, other easy to perform and accurate diagnostic alternatives would be valuable for maternal care. The objective of the study was to assess the diagnostic performance of the TyG index to screen for GDM at 24-28 of pregnancy. A total of 140 pregnant women who received the one-step 2 h 75 g OGTT were included. Overall GDM prevalence was 27.1% according to IADSPG criteria. The mean TyG index value in the GDM group was significantly higher than the TyG index for the no GDM group (4.88 ± 0.70 versus 4.68 ± 0.19, p<.001). A sensitivity of 89% [95% CI 0.75-0.97] and a specificity of 50% [95% CI 0.39-0.60)], accompanied by a high negative predictive value of 93% was observed. No differences were found in maternal and neonatal outcomes irrespective of the TyG cutoff value for GDM. According to our results, the TyG index may be a highly sensitive and easy to perform screening test for GDM.

Use of capillary glucose combined with other non-laboratory examinations to screen for diabetes and prediabetes

AIM

To evaluate the value and feasibility of capillary glucose assessment, combined with other non-laboratory measures, in screening for diabetes and prediabetes in the community.

METHODS

In this cross-sectional study, we assessed fasting capillary glucose, fasting plasma glucose, and both capillary glucose and plasma glucose values after 2-h oral glucose tolerance tests in a total of 3736 samples. We determined the optimal threshold of capillary glucose using receiver-operating characteristic curve analysis. The effect of screening methods using capillary glucose combined with other variables, such as age, BMI and waist circumference, was assessed according to area under the receiver-operating characteristic curve.

RESULTS

There was a strong positive correlation between capillary glucose and venous plasma glucose. The area under the curve for the model using fasting capillary glucose to screen for impaired fasting glucose was 0.722, while that for the model using capillary glucose after a 2-h oral glucose tolerance test to screen for impaired glucose tolerance was 0.916. The area under the curve for the model using fasting capillary glucose to screen for diabetes was 0.835, while that for the model using 2-h oral glucose tolerance test capillary glucose was 0.912. The area under the curve for the model using fasting capillary glucose + 2-h oral glucose tolerance test capillary glucose to screen for diabetes was 0.945. The discriminatory capability of models using capillary glucose was somewhat improved by adding non-laboratory variables.

CONCLUSIONS

Capillary glucose could be an alternative for screening for diabetes and prediabetes, especially in low-resource areas.

Prevalence of gestational diabetes mellitus based on various screening strategies in western Kenya: a prospective comparison of point of care diagnostic methods

Background

Early diagnosis of gestational diabetes mellitus (GDM) is crucial to prevent short term delivery risks and long term effects such as cardiovascular and metabolic diseases in the mother and infant. Diagnosing GDM in Sub-Saharan Africa (SSA) however, remains sub-optimal due to associated logistical and cost barriers for resource-constrained populations. A cost-effective strategy to screen for GDM in such settings are therefore urgently required. We conducted this study to determine the prevalence of gestational diabetes mellitus (GDM) and assess utility of various GDM point of care (POC) screening strategies in a resource-constrained setting.

Methods

Eligible women aged ≥18 years, and between 24 and 32 weeks of a singleton pregnancy, prospectively underwent testing over two days. On day 1, a POC 1-h 50 g glucose challenge test (GCT) and a POC glycated hemoglobin (HbA1c) was assessed. On day 2, fasting blood glucose, 1-h and 2-h 75 g oral glucose tolerance test (OGTT) were determined using both venous and POC tests, along with a venous HbA1c. The International Association of Diabetes in Pregnancy Study Group (IADPSG) criteria was used to diagnose GDM. GDM prevalence was reported with 95% confidence interval (CI). Specificity, sensitivity, positive predictive value, and negative predictive value of the various POC testing strategies were determined using IADPSG testing as the standard reference.

Results

Six hundred-sixteen eligible women completed testing procedures. GDM was diagnosed in 18 women, a prevalence of 2.9% (95% CI, 1.57% - 4.23%). Compared to IADPSG testing, POC IADPSG had a sensitivity and specificity of 55.6% and 90.6% respectively while that of POC 1-h 50 g GCT (using a diagnostic cut-off of ≥7.2 mmol/L [129.6 mg/dL]) was 55.6% and 63.9%. All other POC tests assessed showed poor sensitivity.

Conclusions

POC screening strategies though feasible, showed poor sensitivity for GDM detection in our resource-constrained population of low GDM prevalence. Studies to identify sensitive and specific POC GDM screening strategies using adverse pregnancy outcomes as end points are required.

Trials registration

Clinical trials.gov: NCT02978807, Registered 29 November 2016.

Heterogeneity of glycometabolism in patients with gestational diabetes mellitus: Retrospective study of 1,683 pregnant women

AIMS/INTRODUCTION

To evaluate the glycometabolism and outcomes of gestational diabetes mellitus (GDM) patients according to the International Association of Diabetes and Pregnancy Study Group (IADPSG) criteria in China.

MATERIALS AND METHODS

According to the results of a 75-g oral glucose tolerance test, 1,683 pregnant women were divided into three groups: (i) an increment GDM group (patients meet the IADPSG criteria, but not the previous Chinese criteria); (ii) a stock GDM group (patients meet both criteria); and (iii) a normal glucose tolerance group. Their glycometabolism outcomes, prepregnancy and postpartum body mass index were compared, as were maternal-fetal outcomes.

RESULTS

The IADPSG and previous Chinese criteria diagnosed 12.4% and 5.5% of women with GDM. Pairwise comparison showed significant differences in 1-h plasma glucose, 2-h plasma glucose, HbA1c values and area under curve of glucose among all groups (P < 0.01). The fasting plasma glucose and postpartum body mass index of the stock group were significantly higher than those of the other two groups (P < 0.01). The incidences of hypertensive disorder complicating pregnancy and cesarean section of the normal glucose tolerance group were significantly lower than those of the other two groups (P < 0.001). No significant differences in patient age, prepregnancy body mass index, duration of pregnancy, prevalence of premature labor, premature rupture of membranes, neonatal jaundice, neonatal asphyxia or Ponderal Index were observed, but significant differences in macrosomia and neonatal hypoglycemia were observed (P < 0.05).

CONCLUSIONS

The IADPSG criteria doubled the number of GDM patients. The cases of the increment patients were mild. The IADPSG criteria should be discussed fully before implementation in China.

A critical appraisal and potentially new conceptual approach to screening and diagnosis of gestational diabetes

The aim of this article was a critical appraisal of current GDM screening and diagnosis status as well as a presentation of a potentially new approach to this perinatologic and public health problem of increasing clinical significance. Medline, EMBASE and Cochrane databases were searched. Most professional organisations recommend universal screening at 24-28 weeks of gestation, while some of them state that selective screening could also be recommended. Expert opinions regarding GDM diagnosis significantly differ throughout the world. Authors call for an open and broad professional and scientific discussion and suggest a combination of screening and diagnosis procedures in a form of one-step 1-h screening method, creation of regional GDM diagnostic criteria and standardisation of outcome-based randomised control trials. They also advise introduction of a conceptually new approach, where the risk of hyperglycaemia rather than insisting on GDM diagnosis itself should be detected.

Gestational diabetes mellitus: Screening with fasting plasma glucose

Fasting plasma glucose (FPG) as a screening test for gestational diabetes mellitus (GDM) has had a checkered history. During the last three decades, a few initial anecdotal reports have given way to the recent well-conducted studies. This review: (1) traces the history; (2) weighs the advantages and disadvantages; (3) addresses the significance in early pregnancy; (4) underscores the benefits after delivery; and (5) emphasizes the cost savings of using the FPG in the screening of GDM. It also highlights the utility of fasting capillary glucose and stresses the value of the FPG in circumventing the cumbersome oral glucose tolerance test. An understanding of all the caveats is crucial to be able to use the FPG for investigating glucose intolerance in pregnancy. Thus, all health professionals can use the patient-friendly FPG to simplify the onerous algorithms available for the screening and diagnosis of GDM - thereby helping each and every pregnant woman.

Diagnosis of GDM: a suggested consensus

Despite recent attempts at building consensus, an internationally consistent definition of gestational diabetes mellitus (GDM) remains elusive. Within and between countries, there is disagreement between obstetric, medical, and endocrine groups as to the diagnosis and management of GDM. The current article aims to discuss the background to the controversy of GDM diagnosis and to address issues related to the detection and treatment of GDM in low-, middle-, and high-resource settings. The criteria recommended by the International Association of the Diabetes and Pregnancy Study Groups (IADPSG), the American Diabetes Association (ADA), and the World Health Organization (WHO) are endorsed. We also wish to put into perspective the importance of GDM, both during and after pregnancy, in terms of its relationship to overall women's health.

Strategies for implementing the WHO diagnostic criteria and classification of hyperglycaemia first detected in pregnancy

The World Health Organization (WHO) has recently released updated recommendations on Diagnostic Criteria and Classification of Hyperglycaemia First Detected in Pregnancy which are likely to increase the prevalence of gestational diabetes mellitus (GDM). Any increase in the number of women with GDM has implications for health services since these women will require treatment and regular surveillance during the pregnancy. Some health services throughout the world may have difficulty meeting these demands since country resources for addressing the diabetes burden are finite and resource allocation must be prioritised by balancing the need to improve care of people with diabetes and finding those with undiagnosed diabetes, including GDM. Consequently each health service will need to assess their burden of hyperglycaemia in pregnancy and decide if and how it will implement programmes to test for and treat such women. This paper discusses some considerations and options to assist countries, health services and health professionals in these deliberations.

Fasting capillary glucose as a screening test for ruling out gestational diabetes mellitus

OBJECTIVE

A common approach to screening for gestational diabetes mellitus (GDM) is the testing of all pregnant women with a one-hour, 50 g glucose challenge test (GCT), followed by a diagnostic oral glucose tolerance test (OGTT) when the GCT is positive (≥ 7.8 mmol/L). As only a small subset of those with a positive GCT will have GDM, many more women undergo the OGTT than may be necessary. In this context, we hypothesized that measurement of fasting capillary glucose (FCG) could provide a strategy for reducing the number of unnecessary OGTTs. Thus, we sought to identify a threshold level of FCG below which GDM could be ruled out following a positive GCT, without need for the OGTT.

METHODS

Following a positive GCT, 888 women underwent measurement of FCG prior to their OGTT. We evaluated the test characteristics of FCG for identifying the 209 women diagnosed with GDM on the OGTT.

RESULTS

Fasting capillary glucose was positively associated with each glucose measurement on the OGTT (all P < 0.001) and inversely related to insulin sensitivity and pancreatic beta-cell function (both P < 0.001). As FCG increased, the prevalence of GDM progressively rose (P < 0.001). However, the area under the curve of the receiver-operating characteristic curve for FCG in predicting GDM was modest (0.67). Although using an FCG threshold of 4.8 mmol/L could reduce the number of OGTTs by 28.4%, this approach would miss 18.2% of cases of GDM.

CONCLUSION

Fasting capillary glucose is associated with glycemia, insulin sensitivity, and pancreatic beta-cell function. However, a single FCG measurement is insufficient for reliably ruling out GDM after an abnormal GCT.

Impact of gestational diabetes mellitus screening strategies on perinatal outcomes: a simulation study

AIMS

To evaluate the impact on perinatal outcomes of universal gestational diabetes (GDM) screening based on 1999 WHO and IADPSG diagnostic criteria; to assess the quality of the evidence (GRADE) to support GDM screening.

METHODS

Simulation of a hypothetical cohort of community-based pregnant women with 10% GDM prevalence (1999 WHO). Most parameters were obtained from recent systematic reviews.

RESULTS

Compared to no screening, screening based on 1999 WHO criteria (followed by treatment) reduced the incidence of large for gestational age (LGA) neonates by 0.53% (95% CI 0.37-0.74%; NNS=189) and of preeclampsia by 0.27% (0.10-0.45%; NNS=376). Screening based on IADPSG criteria reduced incidences by 0.85% (0.54-1.29%; NNS=117) and by 0.39% (0.15-0.65%; NNS=257), respectively. Compared to screening based on 1999 WHO criteria, screening with IADPSG criteria reduced the incidence of LGA by 0.32% (0.09-0.63%; NNS=309) and of preeclampsia by 0.12% (0.01-0.25; NNS=808). The quality of evidence for both screening approaches is very low.

CONCLUSIONS

Universal screening for GDM has only a modest impact on pregnancy outcomes. The impact of screening based on IADPSG (vs. WHO, 1999) criteria is slightly larger. However, costs and resources should also be considered in local selection of a screening approach.

Fasting capillary blood glucose: an appropriate measurement in screening for diabetes and pre-diabetes in low-resource rural settings

OBJECTIVE

To evaluate the efficiency of fasting capillary blood glucose (FCG) measurement as compared with fasting venous plasma glucose (FPG) measurement in screening diabetes and pre-diabetes in low-resource rural settings.

SUBJECTS AND METHODS

In 2010, 993 participants were randomly selected from 9 villages in Yunnan province using cluster sampling method. Samples for FCG and FPG test were obtained after demographics and physical examination. The oral glucose tolerance test was performed in parallel as gold standard for diagnosis. Diagnostic capacities of the FCG measurement in predicting undiagnosed diabetes and pre-diabetes were assessed. The performance of FCG and FPG tests was compared.

RESULTS

Fifty-seven individuals with undiagnosed diabetes and 145 subjects with pre-diabetes were detected. The concordance between FCG and FPG levels was high (r = 0.75, p < 0.001). The area under the curve (AUC) for FCG test in predicting diabetes was 0.88 [95% confidence interval (CI) 0.82-0.93] with the optimal cutoff value of 5.65 mmol/l, sensitivity of 84.2%, and specificity of 79.3%. The corresponding values in FPG tests were 0.92 (95% CI 0.88-0.97) (AUC), 6.51 mmol/l (optimal cutoff point), 82.5% (sensitivity) and 98.3% (specificity), respectively. No significant difference was found in the AUC for the two screening strategies.

CONCLUSION

FCG measurement is considered to be a convenient, practicable screening method in low-resource rural communities with acceptable test properties.

The prognostic value of a normal oral glucose tolerance test in pregnant women who tested positive at screening: a validation study

BACKGROUND

Controversies surround a diagnosis of gestational diabetes mellitus (GDM). The objective of this study was to evaluate the oral glucose tolerance test (OGTT) for the prediction of adverse gestational and perinatal outcomes in pregnant women with a positive screening test for diabetes mellitus and a negative diagnosis, i.e. a normal 3-hour OGTT.

METHODS

This validation study evaluated 409 pregnant women who tested positive for diabetes mellitus at screening. Perinatal and maternal outcomes were considered. Sensitivity and specificity were calculated for each of the values of the OGTT as a diagnostic test, with the gold standard being perinatal outcome.

RESULTS

The most frequent risk factors were obesity, arterial hypertension and advanced maternal age. The most common neonatal outcomes were large-for-gestational-age infants, Cesarean delivery and preterm birth. A fasting blood glucose level of 87 mg/dL was the most powerful predictor of adverse perinatal outcome.

CONCLUSIONS

At the cut-off level adopted by the American Diabetes Association, gestational OGTT was able to successfully identify in which pregnant women outcome would be unfavorable.

Gestational diabetes screening: the low-cost algorithm

The American Diabetes Association has endorsed the demanding recommendation by the International Association of the Diabetes and Pregnancy Study Groups (IADPSG) that every pregnant woman should undergo the oral glucose tolerance test (OGTT) for the screening of gestational diabetes mellitus (GDM). The aim of this study was to find out if the fasting plasma glucose (FPG) and newer emerging technologies could simplify the cumbersome IADPSG algorithm. Two FPG thresholds (of the OGTT) were used to rule in and rule out GDM in the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) cohort (n = 23316) and a population at high risk for GDM (n = 10283). For the HAPO cohort and the high-risk population, respectively, FPG thresholds of: (a) ≥ 5.1 mmol/L (specificity 100%) independently ruled in GDM in 1769 (8.3%) women and 2975 (28.9%) women; and (b) ≤ 4.4 mmol/L ruled out GDM in 11526 (49.4%) women (84.1% sensitivity) and 2228 (21.7%) women (95.4% sensitivity). Use of the FPG independently could have avoided 13295 (57.0%) and 5203 (50.6%) OGTTs in the 2 groups. The initial FPG-by significantly reducing the number of cumbersome OGTTs needed-can make the IADPSG recommendations more acceptable worldwide. The number of GDM women missed is population dependent. For low-resource countries, alternative newer and cheaper tests in development hold an exciting future.

Performance of the Roche Accu-Chek active glucose meter to screen for gestational diabetes mellitus using fasting capillary blood

BACKGROUND

Point-of-care (POC) blood glucose measurement using glucose meters is used by diabetes patients to mange their disease. POC glucose testing also is also used in tight glycemic control protocols and as a screening tool for diabetes. We report the performance and effectiveness of the Accu-Chek® Active (Roche Diagnostics GmbH, Mannheim, Germany) glucose meter to screen for gestational diabetes mellitus (GDM) using blood fasting capillary glucose (FCG).

METHODS

To screen for GDM, 1,465 pregnant women underwent an oral glucose glucose tolerance test. Correlation between the FCG and fasting plasma glucose (FPG) levels was determined by Passing and Bablok regression analysis. Total error (TE) of the glucometer was ascertained using the Bland-Altman method with the DXC-800 analyzer (Beckman-Coulter Instruments, Brea, CA) as the reference method. The area under the receiver operator characteristic curve was used to analyze the performance of the FCG to predict GDM.

RESULTS

FPG and FCG identified 361 (24.6%) and 338 (23%) women as having GDM, respectively. The Bland-Altman TE at 95% limits of agreement was -11.1% to 10.8%. The area under the receiver operator characteristic curve was 0.953 (95% confidence interval 0.943 to 0.964).

CONCLUSIONS

The Roche Accu-Chek Active glucometer meets analytical and clinical quality requirements. A TE of±15% is acceptable for glucose meters used in ambulatory care, including home self-monitoring of blood glucose, and different TE targets should be set for acute critical care settings.

Definition, epidemiology, risk factors

Gestational diabetes mellitus is defined as glucose intolerance that begins or is first recognized during pregnancy. Its prevalence, generally situated between 2-6%, may reach 10-20% in high-risk populations, with an increasing trend across most racial/ethnic groups studied. Among traditional risk factors, previous gestational diabetes, advanced maternal age and obesity have the highest impact on gestational diabetes risk. Racial/ethnic origin and family history of type 2 diabetes have a significant but moderate impact (except for type 2 diabetes in siblings). Several non traditional factors have been recently characterized, either physiological (low birthweight and short maternal height) or pathological (polycystic ovaries). The multiplicity of risk factors and their interactions results in a low reliability of risk prediction on an individual basis.

Gestational diabetes: an evaluation of serum fructosamine as a screening test in a high-risk population

AIM

To evaluate the value of serum fructosamine as a screening test for gestational diabetes mellitus (GDM).

METHODS

849 pregnant women underwent the one-step 75 g oral glucose tolerance test (OGTT) for universal screening of GDM. The fasting serum fructosamine (cFruc) was assessed using the area under the receiver operating characteristic curve (AUC). The GDM diagnostic criteria used were those of the American Diabetes Association; however, the cFruc performance was also evaluated using criteria of the World Health Organization, Australian (ADIPS), European (EASD) and International Association of Diabetes and Pregnancy Study Groups (IADPSG).

RESULTS

113 (13.3%) women had GDM. The AUC of the cFruc was 0.60 (95% CI 0.54-0.66). A cFruc threshold of 237 μmol/l achieved an acceptable sensitivity of 85.8% (95% CI 78.0-91.0%), but the associated specificity remained poor at 23.4% (95% CI 20.0-27.0%) with a positive predictive value of just 14.7%. Overall, over 4 out of 5 pregnant women, being over this cutoff, would need the confirmatory OGTT. No cFruc threshold reached acceptable likelihood ratios to rule-in or rule-out GDM. The AUC for cFruc remained unacceptable independent of the diagnostic criteria.

CONCLUSIONS

Despite all the advances in technology, serum fructosamine is a poor test to screen for GDM.

Gestational diabetes mellitus: simplifying the international association of diabetes and pregnancy diagnostic algorithm using fasting plasma glucose

OBJECTIVE

To determine the impact of the International Association of Diabetes and Pregnancy Study Group (IADPSG) criteria on 1) gestational diabetes mellitus (GDM) diagnosis compared with the American Diabetes Association (ADA) criteria and 2) the fasting plasma glucose (FPG) to predict GDM.

RESEARCH DESIGN AND METHODS

In 10,283 pregnant women undergoing a 75-g oral glucose tolerance test (OGTT) for universal screening of GDM, two FPG thresholds (of the OGTT) were used to rule in and to rule out GDM.

RESULTS

The IADPSG and ADA criteria identified GDM in 3,875 (37.7%) women and 1,328 (12.9%) women, respectively (P < 0.0005). FPG thresholds of >or=5.1 mmol/l ruled in GDM in 2,975 (28.9%) women with 100% specificity, while <4.4 mmol/l ruled out GDM in 2,228 (21.7%) women with 95.4% sensitivity. FPG independently could have avoided the OGTT in 5,203 (50.6%) women.

CONCLUSIONS

The IADPSG criteria increased GDM prevalence nearly threefold. By circumventing a significant number of OGTTs, an initial FPG can greatly simplify the IADPSG diagnostic algorithm.

Screening for hyperglycaemia in pregnancy: Consensus and controversy

Policy decisions on whether to implement screening programmes depend on whether the proposed programmes meet a set of criteria laid down by the World Health Organization. Screening for hyperglycaemia in pregnancy (HGP) does not meet all the criteria. However the case for screening has been strengthened by a number of recent developments, including: rising prevalence of HGP because of increasing maternal age and BMI; the results of the Hyperglycaemia and Adverse Pregnancy Outcomes study, showing that adverse effects of HGP are seen over a wider range of plasma glucose levels than previously thought; two large trials which showed the benefits of treating lesser degrees of HGP; trials showing that metformin and glibenclamide were effective and safe alternatives to immediate insulin in those without good control on lifestyle measures alone. However uncertainties remain around the threshold for treatment, and on the best screening strategy.